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The Yakovlev design bureau began work on an advanced trainer based on the successful Yak-3 fighter in mid 1944, although the trainer was of low priority owing to the ongoing Second World War.[1] The first prototype of the new trainer, designated Yak-UTI or Yak-3UTI flew in late 1945. It was based on the radial-powered Yak-3U, but with the new Shvetsov ASh-21 seven-cylinder radial replacing the ASh-82 of the Yak-3U.[2][nb 1] It used the same all-metal wings as the Yak-3U, with a fuselage of mixed metal and wood construction. Pilot and observer sat in tandem under a long canopy with separate sliding hoods. A single synchronisedUBS 12.7 mm machine gun and wing racks for two 100 kg (220 lb) bombs comprised the aircraft's armament.[3]

An improved prototype flew in 1946, with revised cockpits and a modified engine installation with the engine mounted on shock absorbing mounts.[2] This aircraft successfully passed state testing in October 1946, with production beginning at factories in Saratov and Leningrad in 1947.[4]

Production Yak-11s were heavier than the prototypes, with later batches fitted with non-retractable tail wheels and revised propellers. A 7.62 mm ShKAS machine gun was sometimes fitted instead of the UBS, while some were fitted with rear-view periscopes above the windscreen.[4] In total, Soviet production amounted to 3,859 aircraft between 1947 and 1955. with a further 707 licence-built by Let in Czechoslovakia as the C-11.[5]

In 1951, Yakovlev revised the design of the Yak-11, adding a retractable tricycle landing gear, with two variants proposed, the Yak-11U basic trainer and Yak-11T proficiency trainer, which carried similar equipment to contemporary jet fighters. The new aircraft had reduced fuel capacity and was unsuitable for operations on rough or snow-covered runways, and so was rejected for Soviet service, although a few examples were built in Czechoslovakia as the C-11U.[6]

The Yak-11 entered service in 1947, serving as a standard advanced trainer with the Soviet Air Forces and DOSAAF.[7] Both Yak-11 and C-11 were used in all Warsaw Pact countries and were exported to eighteen countries, including many African, Middle Eastern and Asian countries.[4]

Due to its Yak-3 lineage, the Yak-11 has recently seen widespread popularity among warbird enthusiasts. Highly modified versions of the Yak-11 can be frequently seen at air races. About 120 Yak-11s remain in airworthy condition.